1. Field of the Invention
The present invention is directed to a liner retention system for a reciprocating pump. In particular, the present invention is directed to a novel liner retention system for reciprocating mud pumps used in drilling and workover rig applications, and well servicing pumps such as stimulating and cementing.
2. Background of Invention
Drilling fluid (sometimes referred to as “drilling mud”), which is often times a petroleum or water based fluid product, is used in drilling and workover rig applications.
Drilling fluid serves a number of important functions in the drilling operations. The drilling fluid serves to assist in cleaning the bottom of the wellbore hole and transports drill cuttings to the surface where they are removed. The drilling fluid also cools the drill bit and lubricates the drill stem. Additionally, the drilling fluid assists in supporting the walls of the wellbore and discourages entry of fluids into the well. Finally, the drilling fluid can reveal the presence of oil, gas or water that may enter the fluid from a formation being drilled and may reveal information about the formation through drill cuttings. A viscous drilling fluid will be capable of transporting more and heavier cuttings so viscous drilling fluid is encouraged and often additives are utilized to increase viscosity.
The drilling fluid at a drilling or workover rig site is utilized in a circulating system so that the drilling fluid may be reused. The time required for the drilling fluid to travel from pump suction to pump suction is known as a complete cycle.
Mud tanks, when part of a mud circulation system, can supply mud to a pump or pumps to begin circulation, receive the drilling fluid circulated out of the well and store reserve mud.
A reciprocating pump or pumps are utilized to move the drilling fluid from the surface through a series of pipes including a stand pipe and rotary hose and then downhole to the subterranean drilling location. The drilling fluid will often be moved thousands of feet down drill pipe and out small nozzles in a drill bit. Thereafter, the pumps circulate the drilling fluid back to the surface through an annulus where the drilling mud is passed through various conditioning equipment. The equipment may include a vibrating screen assembly and separator mechanisms to remove entrained solids such as rocks or drilling cuttings. Other equipment may include degassers and mud agitators.
A reciprocating pump is a positive displacement pump. A plunger or piston reciprocates (moves back and forth) inside a cylinder which in the present case is a replaceable cylindrical liner. The reciprocating movement of the piston displaces or moves the drilling fluid. Drilling rigs have utilized both single-acting triplex pumps and double-acting duplex pumps.
Mud pumps are known to operate at up to 2200 horsepower. These pumps can include cylinder liners which are required to be frequently changed and also inspected from time to time.